Vacuum-tube lighting.



Patented luiy 9, [90L D. MOF. MOORE.

VACUUM TUBE LIGHTING.

' (Application filed. Dec. 10, 1900.) (No Model.) 5 Sheetg-Sheet l.

am f'\' I A 50 A v A N' w .3 [Q m v\\\\\\\\ Wang/3AM: snnavlom v I 33mg UHsZsMMDTLW V j J3 5M 4% I 4 L344 I M W I R I. d. e t n e t. a P. 6 NM am Mm U m E .Bm FUN cm M .um Dun.v *II\ V (No Model) 5 Sheets-Sheet 2.

v Patented July 9, l90l. D. McF. MOORE.

VACUUM TUBE LIGHTING.

(Application filed Dec. i0, 1900.

5 Shaets-Sheet 3.

(No Model.)

91 bn wm 2 nvenTov (mm m z.

No. "678,302. Patented July 9, I90l.

D. MGF. MOORE.

VACUUM TUBE LIGHTING.

(Application filed Dec. 10, 1900. (No Model.) 5 Sheets-Sheet 4.

No. 678,302. Patented July 9, 19m.

IJQMcF. MOORE;

' VACUUM TUBE uamme.

(Application filed 1m. 10, i900. Q 5 Sheets-Sheet 5.

Suva/rank Un tes STATE PATENT FFICE;

DANIEL MOFARLAN MOORE, OF NEWARK, NEW/V JERSEY, ASSIGNOR TO THE MOORE ELECTRICAL COMPANY, OF NEW YORK, N. Y.

VACUUM-TUBE LIGHTING.

SPECIFICATION forming' part of Letters Patent No. 678,302, dated July 9, 1901.

Application filed December 10, 1900. Serial No. 39,313. (No model.)

T0 at whom it may concern.-

Be it known that I, DANIEL MCFARLAN MOORE, a citizen of the United States, and a resident of Newark, in the county of Essex and State of New Jersey, (with post-office address as above,) have invented certainnew and useful Improvements in Vacuum-Tube Lighting, of which the following is a specification.

This invention relates to a system of electric lighting devised by me wherein vacuumtubes are excited to luminosity by the direct application of alternating electromotive forces obtained from a dynamo-electric generator and impressed directly upon said tubes or indirectly through a suitable static transformer.

My present invention relates more particularly to the form of impressed electromotive force and has a threefold object in view: first, to operate the lamps, with a low voltage on the circuit of the lamps, thereby diminishing the dangers from fire, destructive effects upon the insulation of the conductors, or injury to persons due to high voltages; second, to produce a high illumination with a low consumption of power, thereby adding to the efficiency of the system in operation, and, third, to increase the life of the lamp.

Afurther object of my invention is to eliminate or diminish the striations in the tubes when excited to luminosity.

Briefly speaking, my invention consists in applying to the tubes for'the purpose of exciting them to luminosity a uniform succession rapidly-varying electromotive force, the waves or pulses of which may conveniently be stated as being of peaked form and as distinguished from the form of wave or impressed electromotive force heretofore employed in that each pulse of the electromotive force instead of beginning to rise immediately after the zero-point of the succession of waves continues for a considerable portion of the time between zero-points at a 10W potential or voltage and then rises quickly or sharply to its maximum and immediately falls back toward the zero-line, and then continues for the balance of the pulse at a low potential or voltage until the next zero-point is reached, whereas the waves or pulses heretofore employed begin to rise immediatelyfrom the zero with more or less abruptness and continue at a high potential or voltage for the major portion of the interval between zero-- points, the major portion of the drop of potential taking place at or near the succeeding zero and with more or less abruptness, depending upon the particular form of wave. The latter form of wave may be conveniently described as one having a Wide top and a mean of electromotive force which is comparatively large, so that not only is the total amount of energy consumed or applied by each pulse or wave of electromotive force large, but the actual voltage of the circuit as measured by the voltmeter shows a comparatively high effective potential which might do damage to persons or property. I have discovered that a great deal of the energy thus applied is ineffective in exciting the tubes to luminosity,-

and When an attempt is made to use high voltages such prior form of Wave possesses the disadvantage that it is more liable to break down the insulation and increases the danger of fire. In the improved form of wave employed by me the total amount of energy represented by each pulse is small 5 but the effective action in exciting the tubes to luminosity being due to the sudden rise of potential accompanied more or less by the suddenness of the drop, and such rise being at a very high rate, the illuminating effects are not only as large as those effected by the past forms of wave heretofore used, but even exceed the same for the total amount of power consumed in the generator. I find, further, that from this form of Wave marked advantages also accrue in adding to the length of life of the lamp and in ridding it of the obj ectionable striations which are commonly met with. j

The form of electromotive-force wave employed by me maybe derived from any form of generator adapted to convert mechanical into electrical energy by the principle of magneto-electricity. Ihavedevisedaspecial form of generator particularly well adapted to produce'the improved form of wave and, further, so organized as to preserve one of the characteristics of the machine described in my prior patent, No. 644,995-to Wit., a

constancy of the flux in the magnetic circuit of the machine. I have also discovered that by lowering the period or frequency of the exciting impulses applied to the tubes or lamps the life of the lamp will be increased without, however, any corresponding diminution in the degree of luminosity. Heretofore in this art it has been considered necessary to use very high frequencies in order to secure any reasonable degree of luminosity, and the fact that the life of the lamp could be increased and a luminosity of practical intensity at the same time secured by lowering the frequency has not been known nor recognized. In carrying out this part of my invention any form of electromotive-force wave may be employed; but I prefer to employ the improved form of exciting electromotive force herein described, since it is particularly adapted for exciting the tube with a low frequency, so as to increase the life of the lamp; but it also permits a low voltage to be employed.

Another feature of my invention relates to the manner of reducing or eliminating the striations in the tubes of a vacuum-tubelighting system. This, I have discovered, may be accomplished by constructing the dynamo which generates the alternations of exciting electromotive force of the required voltage and frequency in such manner that it shall have a minimum of self-induction.

In the accompanying drawings, Figure 1 showsdiagrammaticallyandin approximately accurate form one of the kinds of Wave of electromotive force heretofore employed, said waves being shown as alternating, although they might be modified so as to be all of the same sine or polarity; and Fig. 2 illustrates diagrammatically one of the shapes of the improved wave which forms the subject of the present invention. Fig. 3 illustrates the form and proportion of related fixed and movable poles in a machine adapted to produce the form of wave illustrated in Fig. 1, and Fig. 4 shows the relation and the proportion of the stator and rotor or fixed and movablepoles of an improved machine devised "by me for the purpose of generating the form of alternating electromotive-force wave illus trated in Fig. 2. Fig. 5 is a front elevation and partial vertical section of an improved form of dynamo-generator, and Fig. 6 is an end elevation of the same. Fig. 7 is an enlarged cross-section of the iron channel-ring or annulus used for the field of the machine. Fig. 8 shows a form of vacuum-tube lamp adapted for use in my improved system of lighting. Fig. 9 illustrates in side elevation a form which the dynamo may take when it is desired to operate the same by an ordinary electric motor, thus making a self-contained motor and dynamo adapted to be attached to any power-circuit and to furnish a suitable excitation for the vacuum-tube. Fig. 10 illustrates diagrammatically that feature of my invention which consists in operating incandescent lamps and vacuum-tube lamps together from the same circuit-wires or d yuamos. Figs. 11 and 12 illustrate in side elevation and in vertical cross-section a modilication in the form of the dynamo-machine.

Referring to Fig. 1, the pole-faces of the cores for the generating-coils in a dynamomaohine adapted to produce the form of electromotive -force wave illustrated are indicated by the numeral 2. The relation of the width of these pole-faces to the space be tween the poles, as will be seen, is approximately equal-that is, the spaces are equal to the width of the pole-faces-and if said poles or polar projections be wound with a suitable winding passing in reverse direction around said poles or projections alternately and be subjected to the action of a rotating iield having polar projections of substantially the form and proportion illustrated in Fig. an alternating electromotive force of approximately the form indicated in Fig. 1 would be developed. As will be seen, the top of each wave or pulse is comparatively wide, and this would be the case with any sine-wave form of alternating electromotive force-that is to say, the wave would continue at a high mean of electromotive force for a large proportion of the interval between the zero-points. The particular wave form shown approaches, however, more closely the square-topped form de scribed in my prior patent, No. 646,858.

The improved form of wave heretofore designated as the peaked form and illustrated in Fig. 2 may be obtained by a modification in the relative widths of the pole-faces on the polar projections 2 as compared with the width of the space between them, this modification consisting substantially in widening the intervening space and shortening the pole-face in the direction of the movement of the armature pole, so that the slot or space will be wider than the pole-face. This disproportion of slot and pole-face is shown as carried out to the extent of making the relation of space and face approximately eight to one to produce theparticular pointedness or peakedness of wave shown. It will be understood that a less disproportion might exist with of course a corresponding departure from the characteristic of the improved wave, as already described. I contemplate 'in practice, however, a still larger proportion of slot to tooth, thus giving the wave a still more pointed or peaked form and securing in a higher degree the results aimed at. It will be observed that this form of wave possesses in high degree the characteristic of a high rate of change in its increasing and also in its diminishing potential or voltage. This form or character of wave possesses also the further advantage that the actual voltage on the circuit-wires supplied by the machine as measured by a voltmeter continually connected to the circuit-wires and which would indicate the effective and destructive voltage under ordinary conditions is less than with that form shown in Fig. 1, although the maximum electromotive force of each wave shown in Fig. 2 is decidedly greater than that of Fig. 1. lVhile therefore the form of Fig. 2 is better adapted to excite the tubes to luminosity because of the higher electromotive force of each wave and because to some extent'of its higher rate of change or higher bombarding action, it is less liable to do damage in actual use when the dynamo is made to develop the electromotive force of a voltage and frequency best suited to the purposes of the system. This difference in the voltage or potential of the circuit, arising from the difference in the form of wave, is indicated in Figs. 1 and 2. Thus, for instance, the wave of the Fig. 1 form might, with a given frequency, give a volt-meter reading on the circuit the same as that indicated by the horizontal line 50, while that given on the circuit by the form of wave shown in Fig. 2 would show a lesser Voltage on the circuit, even as low proportionately as that indicated by the horizontal line 51, although the actual electromotive force of each pulse, as obtained or observed by plotting through the momentary contact method, wouldzshow in the case of the wave of Fig. 2 a much higher electromotive force for each in dividual wave-pulse.

The form shown in Fig. 2 may be generated by a dynamo whose field and armature teeth are related or proportioned as indicated in Fig. 4c. The polar projections or teeth 2 project from a suitable magnet and are wound, as well understood in the art, with a coil whose direction is reversed on said poles alternately. The field or rotor portion of the machine has polar teeth or projections 3, all of like polarity, which pass said polar projections 2 in rapid rotation and produce the varying magnetic flux in the projections 2, that serve to set up alternating electromotive forces. Said projections may be in a magnetic circuit generated or maintained by a suitable field-coil, wound on a mass of iron, whose magnetic circuit finds its way through the said poles in any well known wayas, for instance, in the manner described in my prior patent, No. 644,995. As will be seen, the length of the polar projections 3 as compared to the distances from pole to pole 21s such as to preserve a constant magnetic flux, since as the polar projection of the armature uncovers one pole 2 it covers in the same degree the next succeeding pole of the dynamo.

Referring to Figs. 4, 5, and 6, the details of the dynamo-generator are more fully illustrated. The field-magnet of the machine is indicated by the numeral 4. Said field-magnet may consist of an annulus of any magnetic material, having one face hollowor recessed to receive the exciting-coil 6, furnished with constant current from any source. The

edges of the annulus constitute the two poles of the field-magnet. The toothed pole-face at one edge, whereby the several poles are formed, may conveniently be constructed by attaching to one edge of the annulus a laminated toothed ring, formed of a number of sheets of metal superposed upon one another and bolted or secured to the edge of the ring, as shown. Between said laminated ring and the opposite edge of the annulus the mass of iron having the polar projections 3 is caused to rotate to produce the varying magnetic flux in the projections 2. The field-magnet 4: is preferably mounted or supported on a base 7, which carries the standards in which are mounted the bearings for the shaft 8. Said shaft carries adisk, of steel or other suitable material, constituting a spider or support 9, to Whose edge is bolted the ring which has the polar projections 3. Said rotor consists, preferably, of a number of sheets of iron toothed at their edge to form the polar projections 3 and superimposed and bolted in any suitable manner to the edge of the disk or frame 9. The frame 9 may consist of a thin disk of sheet-steel clamped upon the shaft, as shown. WVhen rotated at high speeds, it will maintain its form and rigidity through the action of the centrifugal forces generated. The form and construction of the field and armature and the manner of mounting and rotating the rotatable parts may obviously be varied without departing from the invention.

In Fig. 8 I have shown one of the lamps heretofore employed by me and to which the form of alternating electromotive forces in dicated in Fig. 2 may be applied for the purpose of exciting said lamp to luminosity. Said lamp is of the general form heretofore used by me and comprises a tube of glass elongated and of preferably uniform crosssection and containing a rarefied gas, such as air rarefied to the degree best suited for producing luminosity, as well understood in the art. The tube is provided at its ends with suitable conducting-caps, to which the circuit-wires charged with the alternating electromotive forces are connected.

The form of wave herein described is especially adapted to securing these improved results-namely, a low mean voltage of impressed electromotive force (thus permitting a very wide departure from the practice of other inventors, who have always considered it necessary to employ exceedingly high voltages) and comparatively low frequencies, with a total minimum consumption of energy. It is also especially adapted to secure increased life in the lamp, since the total electrolytic actions produced in the same are largely lowered and the electromotive force may be developed from a dynamo-machine without resorting to excessively high speeds or excessively small subdivisions of armature and field poles-troubles which are necessarily associated with high frequencies. Voltages as low as one thousand and frequencies as low as fifty thousand periods per minute are consistent with very high degrees of illumination; but an even less voltage or frequency might be employed.

In prior practice in this art, particularly where dynamomachines have been employed, the aim has been to secure high frequencies and high voltages. In fact frequencies as high as one million and upward per minute and voltages as high as one hundred thousand volts have been employed, and in other systems, in which dynamos have not been used, voltages of as high as one hundred and twenty-five thousand volts have been used.

My invention, as will be seen, therefore, in respect to frequency and voltage, independently of particular form of wave, departs widely from prior practice in that I aim at the use of both low voltage and low frequency, and while I have herein stated that I have employed periods of fifty thousand and volts as low as one thousand I do not limit myself to the same, but claim as within my invention frequencies which might be as high as one hundred thousand per minute and voltages which would be such as are permissible in commercial lighting or power distribution with other systems of lighting. IIence, as will be seen, voltages many times higher than one thousand volts might be employed within my invention and yet be very much less than the voltages heretofore employed in vacuum -tube lighting. \Vith even higher limits of voltage and number of periods per minute than those stated as being within the bounds of my present invention or discovery it will be seen that the system containing my invention would be clearly distinguished from prior practice by stating that it uses comparativelylow voltage and frequency in a system of vacuum-tube lighting.

Fig. 9 shows my improved form of machine as mounted for operation by any ordinary type of electric motor, so that by simply attaching the motor to any electric power-supply circuit the form of energy best suited to the operation of vacuum-tubes may be easily and conveniently obtained. As shown in the figure, 15 indicates an electric motor, to one end of which are bolted the arms 16, supporting the field annulus or ring 4, while the disk or spider 9, which carries the rotary member of the machine, is fastened directly to the shaft of the motor 15, as clearly shown in the drawings. The motor itself maybe mounted upon'a suitable standard orframe 17.

In the construction of the dynamo very close attention should be paid to so proportioning or organizing the coils and magnetic parts of the same as to develop the alternating electromotive forces with a minimum of self-induction, since, as I have discovered, the less the self-induction the less the objectionable striations which tend to form in the luminous tubes of a vacuum-tube-lighting system. The necessary volts must be generated from the right number of total turns surrounding the right quantity of iron. For

l example, striations will immediately appear if the volts are generated from too few turns and too much iron, or vice versa.

Fig. 10 illustrates, diagrammatically, that feature of my invention which consists in operating the vacuum-tubes and incandescent lamps from the same circuit. The incandes cent lamps are indicated by the numeral 19 and are shown as coupled to the same supply- Wires as the vacuum-tubes. When said wires are supplied with energy from a machine of the construction hereinbefore described or from any other machine suitably constructed and operated to supply the exciting energy for the vacuumtubes, incandescent lamps, as shown, maybe attached to and rendered in candescent from the same dynamo. Said lamps would be coupled singly in multiple if the machine be constructed to operate with a low enough voltage, or with a higher vol tage the lamps would be run in series, as in dicated by the dotted lines.

While I have described my invention as applied to vacuum-tubes, I do not wish to he understood as limiting myself to lamps of that special form, but contemplate the use of the invention with any form of lamp adapted to be excited to luminosity by electric waves or vibrations of the general character heretofore used for vacuum-tube lamps.

Figs. 11 and 12 illustrate a further modification in the construction of the dynamo. The object is to secure a simple and cheap mechanical construction and to permit the machine to be run with minimum heatingin the iron portions thereof, through which there is a varying magnetic flux. The form of machine illustrated in these figures is,like the form shown in the previous figures, adapted to produce a pulsating electromotive force of the wave form already described as peaked. Fig. 11 is a side elevation showing the proportionate lengths of the polar projections or teeth in the fixed and rotary portions of the machine, and Fig. 12 is a vertical cross-section through a portion of the machine.

In the improved form of machine shown in Figs. 11 and 12 the varying magnetic flux has its path through soft iron made of a laminated mass constructed from sheet-iron or other proper form of iron, whereas in the form previously described the magnetic flux is partially through a cast-iron annulus or ring. The polar projections 2 are formed, as before, at the inner edge of a laminated toothed ring, (seen more clearly in Fig. 12,) said laminated toothed ring being properly clamped in a frame 25 of cast-iron or any other suitable material. The polar projections 3 of the rotating member which serves to produce the varying magnetic flux in the pro jections 2, carrying the generator-coils of the machine, are differently proportioned from those shown in the previous figures; but the distance between the polar projections 2 is, as already explained, greater than the length of the polar faces measured in the direction of the rotating member. Assuming that the rotation is in the direction of the arrow 30, the polar projections, as shown, are of sufficient length to cover not only two adjacent polefaces 2 and the space between them, but overlap the adjoining space a distance which may be stated as extending from the edge of one of the stator-teeth 2 backward toward the front edge of the nearest tooth, one-half the distance of the space between said teeth minus one-half the width of a stator-tooth.

The exciter-coils of the machine are properly connected or operated to cause the polar projections 2 to exhibit alternate north and south poles, and the rotor-teeth 3 in bridging adjacent poles act as an armature for completing the magnetic circuit between said adjacent poles. The general path of the magnetic iiux for each magnetic circuit thus closed is indicated by the dotted lines at 40 in Fig. 11. 1

The exciting-coils may be wound directly upon the teeth or projections 2, or, as indicated at 41, may be wound around the annulus or ring from which said teeth 2 project. The windings 41 would be repeated and applied or fed with exciting-current in such way as to produce consequent poles in the projections 2, which would be, as already described, alternately north and south proceeding circumferentially. The generator-coils applied upon the polar teeth 2 would be connected up reversely in series so that the electromotive forces excited in them would conspire.

As will be seen, there is no varying magnetic flux in this form of machine in the castiron frame 25; but said fiuxis entirelythrough the soft-iron laminated annulus from which the teeth 2 project and through the laminated iron mass of which the projections 3 in the rotor are formed.

In the drawings I have shown the stator as furnished with eight projections 2, and the rotor as furnished with four of the projections 3. WVith this form and proportion of rotor and statorteeth a pulsation of electromotive force will be produced as four of the stator-teeth have their pole-faces covered by the rotor-teeth 3, and another pulse will be produced as the alternate teeth 2 next behind those covered are uncovered by the statorteeth. By the proportioning of the teeth shown a regular succession of pulses, positive and negative, is obtained, and in one revolution of the machine eight positive and eight negative pulses or eight whole waves or periods of electromotive force would be produced. To secure the same number of waves in a-whole revolution of the machine by the arrangement shown in Fig. 4 would require twice as many stator-teeth and twice as many rotor-teeth as are used with the arrangement shown in Fig. 11. The arrangement or construction of Fig. 11 has therefore the distinct advantage that it may have a low self-induction, because less iron will be required to produce the required electromotive force owing to the fact that with the same number of turns in the generating-coils but one-half the total number of teeth in the rotor and stator are required. The form shown in Fig. 11 also possesses the advantage already stated that as there is no varying magnetic flux in the cast-iron portions of the machine, but said flux takes place wholly in soft iron, the said machine can be designed readily so that it will run cool.

The particular constructions of dynamoelectric machines herein described are not specifically claimed herein, as they form the subject of claims in my application for patent filed April 13, 1901, Serial No. 55,683, nor do I claim herein the combined system of vacuum-tube and incandescent lighting herein described, as this also forms the subject of a claim in the application, Serial No. 55,683, filed April 13, 1901.

What I claim as my invention is- 1. The herein-described improvement in vacuum-tube lighting which consists in exciting the tubes to luminosity by alternating electromotive forces which graphically represented show a wave of peaked form as and for the purpose described.

2. The herein-described improvement in exciting vacuum-tubes to luminosity by alternating electromotive forces whose waves graphically represented have their maximum rate of change at or near the middle of the interval between the zero-points, as and for the purpose described.

3. The herein-described improvement in vacuum-tube lighting which consists in exciting the lamps to luminosity by alternating electromotive forces of comparatively low voltage and frequency as and for the purpose described.

4. The herein-described improvement in vacuum-tube lighting which consists in exciting the tubes to luminosity by a uniform succession, or series of waves or pulses of electromotive force of uniform value and which graphically represented are of peaked form, as and for the purpose described.

5. The herein-described improvement in vacuum-tube lighting which consists in exciting the tubes or lamps to luminosity by waves or pulses of electromotive force derived from a dynamo-machine properly constructed to generate waves or pulses each of which has a high maximum and a low mean electromotive force as and for the purpose described.

6. The herein-described improvement in vacuum-tube lighting which consists in exciting the lamps to luminosity by a succession of waves or pulses of electromotive force'each of which is of low mean but of high maximum value.

7. The herein-described improvement in exciting lamps, substantially such as described, to luminosity, consisting in impressing upon said lamps waves or pulses of electromotive force derived from a dynamo-machine properly constructed to give to each wave or pulse a high maximum and low mean electromotive force as and for the purpose described.

8. The herein-described improvement in vacuum-tube lighting, consisting in exciting the lamps t0 luminosity by a rapidly-recurring succession of Waves or pulses of electromotive force derived from a dynamo-machine properly constructed to reduce the time during which the higher electromotive force shall exist in each interval from zero to zero of the succession of pulses generated.

0. The herein-described improvement in vacuum-tube lighting, consisting in exciting the lamps to luminosity by a succession of Waves or pulses of impressed electromotive force of comparatively low frequency, whereby the life of the lamps may be increased Without substantially decreasing their degree of illumination.

10. The herein-described improvement in vacuum-tube lighting, which consists in exciting the lamps to luminosity by impressing upon them alternating electromotive forces of comparatively low frequency, thereby inl creasing the life of the lamps Without substan tially decreasing their degree of illumination.

11. The herein-dcscribed improvement in vacuum-tube lighting, consisting in exciting the lamps to luminosity by alternating electromotive forces derived from a dynamo-elcctric machine properly constructed as herein described, to have a low or diminished selfinduction, whereby the striations of the tubes may be eliminated or reduced.

12. The herein-described improvement in vacuum-tube lighting which consists in exciting the lamps to luminosity by a series of uniform waves of alternating electromotive force each Wave of which has a high maxi mum of electromotive force and a low mean electromotive force as and for the purpose described.

Signed at New York, in the county of New York and State of New York, this 7th day of December, A. D. 1900.

DANIEL MGFARLAN llJlOORE.

Witnesses:

DELBERT 1 I. DECKER, ETHEL L. LAWLER. 

